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Tigris indexes the `Last-Modified` field for every object stored in a bucket. This can be used to query objects based on their `Last-Modified` index and in-memory filters using a SQL-like syntax through the `X-Tigris-Query` header when using the [ListObjectsV2 API](https://docs.aws.amazon.com/AmazonS3/latest/API/API_ListObjectsV2.html).

The `X-Tigris-Query` field query can be thought of as the `WHERE` clause in a SQL query. For instance, to find all objects with a `Content-Type` of `text/javascript`, set the header as follows:

- `X-Tigris-Query`:
``WHERE `Last-Modified` > "2023-01-15T08:30:00Z" AND `Content-Type` = "text/javascript"``

## Queryable Fields

Tigris supports querying against the following fields:

1. ```Last-Modified```: The date and time the object was last modified in [RFC3339](https://www.ietf.org/rfc/rfc3339.txt) format. **This field is** **indexed and can be used for efficient queries.**
2. ```Content-Type```: The content type assigned during upload. **This field** **can be used as an in-memory filter when combined with `Last-Modified`.**
3. ```Content-Length```: The size of the object. **This field can be used as** **an in-memory filter when combined with `Last-Modified`.**
4. ```key```: The key of the object. **This field can be used as an in-memory** **filter when combined with `Last-Modified`.**
5. ```Event-Type```: The type of the event, this is only supported in [Object Notifications](/content/docs/buckets/object-notifications/index.html).

## Query Requirements

**Important**: Since only `Last-Modified` is indexed, your query must include a condition on `Last-Modified` to enable efficient filtering. Other fields like `Content-Type` and `Content-Length` can be used as additional in-memory filters.

## SQL Operations

Query supports following comparison operators:

1. `=`: Equal
2. `!=`: Not Equal
3. `>` and `<`: Greater than and less than
4. `>=` and `<=`: Greater than or equal and less than or equal
5. `AND`: Combine multiple conditions in a query.

## In Memory Operations

Tigris supports `IN`, `NOT IN`, and `REGEXP` operators for filtering results. Since these operations are performed in memory, they must be combined with a `Last-Modified` condition. For example:

1. ``WHERE `Last-Modified` > "2022-06-10T14:20:00Z" AND `Content-Type` = "text/plain" AND key REGEXP ".*\.txt$"``
2. ``WHERE `Last-Modified` > "2023-03-22T09:45:00Z" AND `Content-Length` > 1024 AND `Content-Type` IN ("text/javascript", "text/css")``.
3. ``WHERE `Last-Modified` > "2021-11-05T16:15:00Z" AND `Content-Length` != 65536 AND `Content-Type` NOT IN ("text/plain", "text/html")``.

## Order By

You can sort the list using `ORDER BY`. For example, to retrieve all items smaller than `64KB` ordered by `Content-Type`:

- ``WHERE `Last-Modified` > "2023-08-14T11:30:00Z" AND `Content-Length` < 65536 ORDER BY `Content-Type``

## Example Queries

Example queries that can be performed:

1. ``WHERE `Content-Type` = "text/plain" ORDER BY `Last-Modified``
2. ``WHERE `Last-Modified` > "2023-05-18T13:20:00Z" AND `Content-Type` >= "text/c" AND `Content-Type` < "text/j"``
3. ``WHERE `Last-Modified` > "2021-09-27T10:15:00Z" AND `Content-Length` > 0 ORDER BY `Last-Modified` ASC``
4. ``WHERE `Content-Length` != 65536 AND `Content-Type` = "text/plain" ORDER BY `Last-Modified``

## Next Steps

- Check out the [Example Usage](/content/docs/sdks/s3/aws-go-sdk/#metadata-querying/index.html) for more details on how to use them in your application.

- [Queryable Fields](/content/docs/objects/query-metadata/#queryable-fields/index.html)
- [Query Requirements](/content/docs/objects/query-metadata/#query-requirements/index.html)
- [SQL Operations](/content/docs/objects/query-metadata/#sql-operations/index.html)
- [In Memory Operations](/content/docs/objects/query-metadata/#in-memory-operations/index.html)
- [Order By](/content/docs/objects/query-metadata/#order-by/index.html)
- [Example Queries](/content/docs/objects/query-metadata/#example-queries/index.html)
- [Next Steps](/content/docs/objects/query-metadata/#next-steps/index.html)